cloudflare/pint
Publicmirrored from https://github.com/cloudflare/pintAvailable
internal/promapi/metadata.go
133lines · modecode
| 1 | package promapi |
| 2 | |
| 3 | import ( |
| 4 | "context" |
| 5 | "encoding/json" |
| 6 | "fmt" |
| 7 | "io" |
| 8 | "log/slog" |
| 9 | "net/http" |
| 10 | "net/url" |
| 11 | "time" |
| 12 | |
| 13 | v1 "github.com/prometheus/client_golang/api/prometheus/v1" |
| 14 | "github.com/prymitive/current" |
| 15 | ) |
| 16 | |
| 17 | type MetadataResult struct { |
| 18 | URI string |
| 19 | Metadata []v1.Metadata |
| 20 | } |
| 21 | |
| 22 | type metadataQuery struct { |
| 23 | timestamp time.Time |
| 24 | ctx context.Context |
| 25 | prom *Prometheus |
| 26 | metric string |
| 27 | } |
| 28 | |
| 29 | func (q metadataQuery) Run() queryResult { |
| 30 | slog.Debug( |
| 31 | "Getting prometheus metrics metadata", |
| 32 | slog.String("uri", q.prom.safeURI), |
| 33 | slog.String("metric", q.metric), |
| 34 | ) |
| 35 | |
| 36 | ctx, cancel := q.prom.requestContext(q.ctx) |
| 37 | defer cancel() |
| 38 | |
| 39 | var qr queryResult |
| 40 | |
| 41 | args := url.Values{} |
| 42 | args.Set("metric", q.metric) |
| 43 | resp, err := q.prom.doRequest(ctx, http.MethodGet, q.Endpoint(), args) |
| 44 | if err != nil { |
| 45 | qr.err = fmt.Errorf("failed to query Prometheus metrics metadata: %w", err) |
| 46 | return qr |
| 47 | } |
| 48 | defer resp.Body.Close() |
| 49 | |
| 50 | if resp.StatusCode/100 != 2 { |
| 51 | qr.err = tryDecodingAPIError(resp) |
| 52 | return qr |
| 53 | } |
| 54 | |
| 55 | meta, err := streamMetadata(resp.Body) |
| 56 | qr.value, qr.err = meta, err |
| 57 | return qr |
| 58 | } |
| 59 | |
| 60 | func (q metadataQuery) Endpoint() string { |
| 61 | return "/api/v1/metadata" |
| 62 | } |
| 63 | |
| 64 | func (q metadataQuery) String() string { |
| 65 | return q.metric |
| 66 | } |
| 67 | |
| 68 | func (q metadataQuery) CacheKey() uint64 { |
| 69 | return hash(q.prom.unsafeURI, q.Endpoint(), q.metric) |
| 70 | } |
| 71 | |
| 72 | func (q metadataQuery) CacheTTL() time.Duration { |
| 73 | return time.Minute * 10 |
| 74 | } |
| 75 | |
| 76 | func (p *Prometheus) Metadata(ctx context.Context, metric string) (*MetadataResult, error) { |
| 77 | slog.Debug("Scheduling Prometheus metrics metadata query", slog.String("uri", p.safeURI), slog.String("metric", metric)) |
| 78 | |
| 79 | key := "/api/v1/metadata/" + metric |
| 80 | p.locker.lock(key) |
| 81 | defer p.locker.unlock(key) |
| 82 | |
| 83 | resultChan := make(chan queryResult) |
| 84 | p.queries <- queryRequest{ |
| 85 | query: metadataQuery{prom: p, ctx: ctx, metric: metric, timestamp: time.Now()}, |
| 86 | result: resultChan, |
| 87 | } |
| 88 | |
| 89 | result := <-resultChan |
| 90 | if result.err != nil { |
| 91 | return nil, QueryError{err: result.err, msg: decodeError(result.err)} |
| 92 | } |
| 93 | |
| 94 | metadata := MetadataResult{ |
| 95 | URI: p.publicURI, |
| 96 | Metadata: result.value.(map[string][]v1.Metadata)[metric], |
| 97 | } |
| 98 | |
| 99 | return &metadata, nil |
| 100 | } |
| 101 | |
| 102 | func streamMetadata(r io.Reader) (meta map[string][]v1.Metadata, err error) { |
| 103 | defer dummyReadAll(r) |
| 104 | |
| 105 | var status, errType, errText string |
| 106 | errText = "empty response object" |
| 107 | meta = map[string][]v1.Metadata{} |
| 108 | decoder := current.Object( |
| 109 | current.Key("status", current.Value(func(s string, _ bool) { |
| 110 | status = s |
| 111 | })), |
| 112 | current.Key("error", current.Value(func(s string, _ bool) { |
| 113 | errText = s |
| 114 | })), |
| 115 | current.Key("errorType", current.Value(func(s string, _ bool) { |
| 116 | errType = s |
| 117 | })), |
| 118 | current.Key("data", current.Map(func(k string, v []v1.Metadata) { |
| 119 | meta[k] = v |
| 120 | })), |
| 121 | ) |
| 122 | |
| 123 | dec := json.NewDecoder(r) |
| 124 | if err = decoder.Stream(dec); err != nil { |
| 125 | return nil, APIError{Status: status, ErrorType: v1.ErrBadResponse, Err: fmt.Sprintf("JSON parse error: %s", err)} |
| 126 | } |
| 127 | |
| 128 | if status != "success" { |
| 129 | return nil, APIError{Status: status, ErrorType: decodeErrorType(errType), Err: errText} |
| 130 | } |
| 131 | |
| 132 | return meta, nil |
| 133 | } |
| 134 | |